package demo;

import com.sun.org.apache.bcel.internal.generic.ATHROW;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: Administrator
 * Date: 2023-04-20
 * Time: 8:12
 */
public class LinkedList {
    public LinkedList next;
    public LinkedList prev;
    public int val;

    public LinkedList(int val){
        this.val = val;
    }

    public LinkedList head;
    public LinkedList last;

    //头插法
    public void addFirst(int data){
        LinkedList node = new LinkedList(data);
        if(head == null){
            head = node;
            last = node;
            return;
        }
        node.next = head;
        head.prev = node;
        head = node;
    }
    //尾插法
    public void addLast(int data){
        LinkedList node = new LinkedList(data);
        LinkedList cur  = head;
        if(head == null){
            head = node;
            last = node;
        }else{
            last.next = node;
            node.prev = last;
            last = node;
        }
    }
    //任意位置插入,第一个数据节点为0号下标
    public void addIndex(int index, int data){
        LinkedList node = new LinkedList(data);
        LinkedList cur = head;
        int size = size();
        if( index < 0 || index >= size){
            throw  new Abnormal("在任意位置插入时，下标不合法");
        }
        if(index == 0){
            addFirst(data);
            return;
        }
        if (index == size){
            addLast(data);
            return;
        }
        while(index != 0){
            cur = cur.next;
            index--;
        }
        node.next = cur;
        node.prev.next = node;
        node.prev = cur.prev;
        cur.prev = node;
    }
    //查找是否包含关键字key是否在单链表当中
    public boolean contains(int key){
        LinkedList cur = head;
        while (cur != null){
            if(cur.val == key){
                return true;
            }
            cur = cur.next;
        }
        return false;
    }
    //删除第一次出现关键字为key的节点
    public void remove(int key){
        LinkedList cur = head;
        while (cur != null) {
            if(cur.val == key) {
                if(cur == head) {
                    head = head.next;
                    if(head != null) {
                        head.prev = null;
                    }else {
                        last = null;
                    }
                }else {
                    cur.prev.next = cur.next;
                    if(cur.next != null) {
                        cur.next.prev = cur.prev;
                    }else {
                        last = last.prev;
                    }
                }
                return;
            }else {
                cur = cur.next;
            }
        }
    }
    //删除所有值为key的节点
    public void removeAllKey(int key){
        LinkedList cur = head;
        while (cur != null) {
            if(cur.val == key) {
                if (cur == head) {
                    head = head.next;
                    if (head != null) {
                        head.prev = null;
                    }else {
                        last = null;
                    }
                } else {
                    cur.prev.next = cur.next;
                    if (cur.next != null) {
                        cur.next.prev = cur.prev;
                    } else {
                        last = last.prev;
                    }
                }
            }
            cur = cur.next;
        }

    }
    //得到单链表的长度
    public int size(){
        LinkedList cur = head;
        int count = 0;
        while (cur != null){
            count++;
        }
        return count;
    }
    public void display(){
        LinkedList cur = head;
        while (cur != null){
            System.out.print(cur.val + " ");
            cur = cur.next;
        }
    }
    public void clear(){
        LinkedList cur = head;
        while (cur != null) {
            LinkedList curNext = cur.next;
            cur.prev = null;
            cur.next = null;
            //cur.val = null;
            cur = curNext;
        }
        head = null;
        last = null;
    }

    public LinkedList getIntersectionNode(LinkedList headA, LinkedList headB) {

    }
}
